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The KPA3A is a modular option for the K3S that provides a full 100 watts output while under full control of the K3S Master Controller (MCU).  It is fully factory calibrated and ready for installation upon receipt.

We Are Now Contacting Customers Who Are On The KPA3A Waitlist

If you recently received an email regarding your KPA3A waitlist order, we will need to know your K3/K3S serial number to ensure we send you the correct KPA3A.  Please complete the following steps.

1.  Complete the form below and provide us with your K3/K3S serial number.  Please do not check the Cancel Order box.

2.  Place your order under the Price List/Order section located below the form.

Please note that we are sending KPA3A waitlist emails in batches. Please wait until you receive an email before completing this form and placing your order. 

Cancelling Your Waitlist Order

If you no longer want to purchase a KPA3A, please complete the form below and check the Cancel Order link.  Informing us of your cancellation will make a KPA3A available to the next person on the waitlist.



Customers Not On The KPA3A Waitlist

Orders placed by customers not on the waitlist will be notified if extra KPA3As are available for purchase.

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The KPA3A option consists of three subassemblies: the KPA3A power amplifier, a fan panel to provide cooling, and the KPAIO3A interface module.


The KPAIO3A acts as an interface between the RF board and the KPA3A power amplifier. It includes a relay that allows the KPA3A to be bypassed when it is not needed during low power operations. The cooling fans are also controlled by circuitry on the KPAIO3A. There are four fan speeds, plus OFF, selected automatically based on the measurement of the KPA3A heat sink temperature.

KPA3A Fan Panel

Two fans are mounted on this panel, along with a circuit breaker to protect the KPA3A from accidental short circuits. The fan panel is connected to the KPAIO3A fan connectors and to the heavy 12-volt connections of the KPA3A module.

KPA3A Power Amplifier

The KPA3A Power Amplifier consists of two RF power transistors operating as a broadband push-pull amplifier; a PIN diode TR switch; and associated bias and control circuitry. The KPA3A provides the necessary gain to increase the power output of the K3S or K3 from 10 watts to 100 watts from 1.8 MHz and 54 MHz. A heat sink is provided that, together with the cooling fans, provides the necessary cooling to maintain the operating temperature of the output transistors at a safe level.

The KPA3A is mounted in the K3S/K3 with the circuit side of the board down so that only the heat sink is visible after removing the top cover. Each KP





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